Dental appliance.



P. H. SKINNER.

I DENTAL APPLIANCE. APPLiOATION FILED MAY 17, 1909.

1,0725 1 9. Patented Sept. 9, 1913.

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I NITED srA'rns PATENT clinics.

FRANK n. SKINNER, or a es, ILLINOIS.

DENTAL APILIANCE.

Specification of amusement. Pat te t, 9, 1913 Application filed 17, 1909. Serial No. 496,619.

To all whom it may concern:

Be it known that I,FRANK I-I. SKINNER, a

citizen of the United States, residing at Chicago, in the county of- Cook and State of Illinois, have invented certain new and access to the less accessible teeth of a patients jaw; to provide an instrument which is capable of dolng its work wlth a 1111111- .11111111 offnianipulations liable to disturb a patient; to provide an instrument adapted to. perform its operations rapidly, and that will take up but ve'rylittle space in the instrument case and present a less formidable and alarming appearance than heretofore.

With the above-named general objects in view, my invention consists in the novel crown-pin extractor hereinafter described in detail, illustrated in the drawing and pointed larged several times full size.

out in the appended claims inwhich claims no claim is made to the construction disclosed in a copending application No. 198,515.

In the drawing-Figure 1 is a perspective view of an instrument embodying my invention, held in the grasp of an operators fingers as when it is about to be applied to a crown pin, and showing substantially its size in comparison with an .operators handJ Fig. 2 is a side elevation partly in section of an instrument embodying my invention, en-. Fig. 3 is a vertical section taken substantially on line 33 of Fig. 2. Fig. i is a section taken substantially on line H- of Fig. 2, and Fig.

o is a lower-end view presenting the beaks of the jaws.

In the several views 2 and 3 represent the pin-gripping jaws of the instrument. 4 and 5 represent the beak-portions of said jaws. These jaws are mounted between, and fulcrumed at 6, and 7 to the endsof, a pair of bars 8 and 9, and are spaced apart to permitthe passage of a post 10 between said jaws. The free end of this post has forked portions 11 and 12 arranged to bear against the root of a tooth 13 on opposite sides of .a crown-pin 14 when the latter is gripped by the beaks 4 and 5, as shown in Figs. 2 and 8. Thejaws and the post'exert reciprocal pull and push'forces, the. jaws firmly gripping the pin 1 1 and the"fo rl "11. 12 of the post pushing against the root of the tooth. Both these forces are applied simultaneously with the aidof a single screw and in such a manner that the greater the resistance of the pin and root of tooth the greater will be the gripping force of the jaws, thus automatically regulating the necessary force of the grip without separate manipulation of a means for moving thejawsand also automatically obviating the liability of. misjudging the amount of grip necessary, thus permitting the jaws to lose their grip and necessitating repeated adjustments with a loss of time and possible annoyance to the patient. I accomplish this simultaneous and relatively self adjustable force with the aid of a screw 15' having threaded engagement with a nut 16 provided with ears 17 and 18 pivoted at 19.and 20 to the inner ends of toggledinks 21 and 22 whose outer ends are pivoted at 23 and 2 k to the upper, or power, ends of the'jaws 2 and 8. The n aper end of the screw is provided with alznurled head 25 and its lower end is swiveled to the upper .ing respectively, against the upper edges of the jaw-connecting bars 8 and 9 and the nut 16. The jaws are opened to grip a pin in the manner shown in Fig. 1, where the operator grasps the outeredges of the jaws between his thumb and second finger and presses down upon the knurled head 25 with his index finger. When the pin has been engaged by the jaws they are closed upon said pin by slmply removing the downward pressure upon the screw which permits; the spring 30 to force up the nut 16 and force out the upper ends of the jaws by the outward pressure of the toggle-links as they tend to straighten out. hen the screw is then turned to advance it toward the root or push the post forward the resistance of the root as the parts 11 and 12 of the post begin to bear against it is instantly transmitted to the toggle links thus increasing the grip of the beaks of the jaws upon the pin and the greater the resistance of the pin the greater will be the grip of the jaws upon the pm. If the pin or post yields readily the grip of the jaws will be comparatively light, and vice versa. The operator need not be con cerned about how tightly to gri the pin, need not imposeany strain upon the tooth in attempting to securely tighten the jaws of the device upon the crown-pin, saves the time usually required for such manipulation of the instrument, and is enabled to instantaneously apply the extracting forces.

The provision of a construction which obviates the necessity of a separate screw, or the like, for moving the jaws enables me to make the instrument very short, in fact so short that the instrument may be applied to pins in lower bicuspids and molars no matter how much these may tip toward the median line of the face. This shortening in the length of the instrument also brings the application of the forces closer to the root of the tooth, diminishes the leverage of, and liability to, lateral or bending strains, and enables the dentist or. operator to rest his hand upon adjoining teeth when supporting the instrument during manipulation of the screw. 7

The parts Hand 12 of the post, or the prongs of its fork, are supported against displacement laterally with respect to the beaks of the jaws by being mounted in guide-channels in the form of rabbets 31 in the edges of the beaks of the jaws," as shown most plainly in Fig. 5.

- I claim as my invention 1. In a crown-pin extractor, the combination with a pair of jaws movable relative to each other and a post movable relative to said jaws, said post having a part adapted to rest against the root of a tooth and to said connection for moving said post and jaws.

3; In a crown-pin extractor, the comb1nation with a pair of jaws having their fulcrums linked together, links between the power-ends of said jaws, a longitudinally movable post, and a nut and screw for actuating said links, jaws and post, 7.

4. The combination with a pair of jaws, of a post, a screw, a link connection for fulcrum pivots for said jaws, said connection supporting said screw laterally in one plane, means guiding said screw laterally in a plane at right angles to said first mentioned plane, and meansmoving both jaws and post with the aid of said screw.

5. The combination with a pair of jaws linked together intermediate of their ends,

a pair of links pivoted to the power ends of 1 said jaws, a threaded nut connecting said last mentioned links, a post, and a screw ai 7 having operative connection with said nut and post.

6. The combination with a pair of jaws,

of a link connection for the fulcrums of said jaws, a post, toggle links for moving said jaws, a nut pivoted between the ends of said toggle links, and' a screw having threaded engagement with said nut.

In testimony whereof I have hereunto set witnesses.

FRANK H. SKINNER. Witnesses M. O. ALLEN, J. W. BECKSTROM.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of'l'atents,

Washington, D. G.

my hand in the presence of two subscribing f 

